Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(126)
https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
Autosar Guidelines C++14, example code compile list will be listed.
目的(purpose)
AutosarのC++ GuidelineをOS, 制御のプログラムで利用するにあたって、以下を検討する。
(1)hosted, freestandingのどちらを基本にすべきか。(2)C++2014,C++2017, C++202aのどれを用いると良いか。
(3)どの処理系を併用すると良いか。
-std=c++14, -std=c++17, -std=c++2aの3種類で、複数のコンパイラでコンパイルすることにより、誤(error)、警告(warning)、関数・変数連携(link)、出力(output)、にどのような影響があるかを確認する。
成果(outcome)
複数の処理系の特徴が明確になる。
各標準段階の違いを明確にする。
hostedまたはfreestandingの特徴と課題を明確にする。
A15-1-4.cpp
算譜(source code)
A15-1-4.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(126)A15-1-4.cpp";
//https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
// There is no description about Autosar declear hosted or freestanding.
// If the Autosar intended both depending on the cases, autosar.h can choose one.
// Compile with -DHOSTED work as hosted environment, -DFREESTANDING work as freestanding.
#include "autosar.h"/// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a
using namespace std;/// @line add using
/// @ start AUTOSAR: From here to the "///end AUTOSAR" are from the AUTOSAR code without some code having /// comment in line.
//% $Id: A15-1-4.cpp 272338 2017-03-28 08:15:01Z piotr.tanski $
#include <cstdint>
#include <memory>
#include <stdexcept>
extern std::uint32_t f1();
void fVeryBad() noexcept(false)
{
std::logic_error* e = new std::logic_error("Logic Error 1");
// ...
std::uint32_t i = f1();
if (i < 10)
{
throw(*e); // Non-compliant - fVeryBad() is not able to clean-up
// allocated memory
}
// ...
delete e;
}
void fBad() noexcept(false)
{
std::int32_t* x = new std::int32_t(0);
// ...
std::uint32_t i = f1();
if (i < 10)
{
throw std::logic_error("Logic Error 2"); // Non-compliant - exits from
// fBad() without cleaning-up
// allocated resources and
// causes a memory leak
}
else if (i < 20)
{
throw std::runtime_error("Runtime Error 3"); // Non-compliant - exits
// from fBad() without
// cleaning-up allocated
// resources and causes a
// memory leak
}
// ...
delete x; // Deallocates claimed resource only in the end of fBad() scope
}
void fGood() noexcept(false)
{
std::int32_t* y = new std::int32_t(0);
// ...
std::uint32_t i = f1();
if (i < 10)
{
delete y; // Deletes allocated resource before throwing an exception
throw std::logic_error("Logic Error 4"); // Compliant - deleting y
// variable before exception
// leaves the fGood() scope
}
else if (i < 20)
{
delete y; // Deletes allocated resource before throwing an exception
throw std::runtime_error("Runtime Error 5"); // Compliant - deleting y
// variable before
// exception leaves the
// fGood() scope
}
else if (i < 30)
{
delete y; // Deletes allocated resource before throwing an exception
// again, difficult to maintain
throw std::invalid_argument(
"Invalid Argument 1"); // Compliant - deleting
// y variable before
// exception leaves the
// fGood() scope
}
// ...
delete y; // Deallocates claimed resource also in the end of fGood() scope
}
void fBest() noexcept(false)
{
std::unique_ptr<std::int32_t> z = std::make_unique<std::int32_t>(0);
// ...
std::uint32_t i = f1();
if (i < 10)
{
throw std::logic_error("Logic Error 6"); // Compliant - leaving the
// fBest() scope causes
// deallocation of all
// automatic variables, unique_ptrs, too
}
else if (i < 20)
{
throw std::runtime_error("Runtime Error 3"); // Compliant - leaving the
// fBest() scope causes
// deallocation of all
// automatic variables,
// unique_ptrs, too
}
else if (i < 30)
{
throw std::invalid_argument(
"Invalid Argument 2"); // Compliant - leaving the fBest() scope
// causes deallocation of all automatic
// variables, unique_ptrs,
// too
}
// ...
// z is deallocated automatically here, too
}
class CRaii // Simple class that follows RAII pattern
{
public:
CRaii(std::int32_t* pointer) noexcept : x(pointer) {}
~CRaii()
{
delete x;
x = nullptr;
}
private:
std::int32_t* x;
};
void fBest2() noexcept(false)
{
CRaii a1(new std::int32_t(10));
// ...
std::uint32_t i = f1();
if (i < 10)
{
throw std::logic_error("Logic Error 7"); // Compliant - leaving the
// fBest2() scope causes a1
// variable deallocation
// automatically
}
else if (i < 20)
{
throw std::runtime_error("Runtime Error 4"); // Compliant - leaving the
// fBest2() scope causes
// a1 variable
// deallocation
// automatically
}
else if (i < 30)
{
throw std::invalid_argument(
"Invalid Argument 3"); // Compliant - leaving the fBest2() scope
// causes a1 variable deallocation
// automatically
}
// ...
// a1 is deallocated automatically here, too
}
/// @ end AUTOSAR
int start() { /// @{} for start
cout<< msg << endl;
ShutdownOS() EXIT_SUCCESS;
/// Autosar OS 3.1.1, 2009: 7.1.2.2 Undefined Behaviour in OSEK OS
/// OS425 If ShutdownOS is called and ShutdownHook() returns then the operating system shall disable all interrupts and enter an endless loop.
}
a15-1-4a.cpp
#include "autosar.h"/// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a
using namespace std;/// @line add using
uint32_t f1() {
cout << "f1()"<<endl;
return (uint32_t)true;
}
編纂・実行結果(compile and go)
cpa.sh
$ ../cpa2.sh a15-1-4 a15-1-4a
$ clang++ a15-1-4.cpp a15-1-4a.cpp -std=c++14 -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
rm: a15-1-4l13: No such file or directory
$ clang++ a15-1-4.cpp a15-1-4a.cpp -std=c++17 -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
$ clang++ a15-1-4.cpp a15-1-4a.cpp -std=c++2a -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
$ g++-8 a15-1-4.cpp a15-1-4a.cpp -std=c++14 -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
$ g++-8 a15-1-4.cpp a15-1-4a.cppp -std=c++17 -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
$ g++-8 a15-1-4.cpp a15-1-4a.cppp -std=c++2a -Wall
Rule A15-1-4 (required, implementation, partially automated)If a function exits with an exception, then before a throw, the function shall place all objects/resources that the function constructed in valid states or it shall delete them.(124)A15-1-4.cpp
検討事項(agenda)
1. 自律(freestanding)環境. 接待(hosted)環境
C++N4606 1.4 Implementation compliance p.4
2. 対応OSの水準、対応通信規約、応用機能による分類
freestanding用の関数、ライブラリ等
3. C++2014, C++2017, C++202aの比較項目
本件なし
4. clang++, g++の比較検討項目
本件なし
5. 役立つまたは意味のある出力
参考文献(reference)
C++N4741 2018
Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/n4741.pdf
C++N4741, 2018 Standard Working Draft on ISO/IEC 14882 sample code compile list
https://qiita.com/kaizen_nagoya/items/3294c014044550896010
C++N4606 2016
Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
C++N4606, 2016符号断片編纂一覧(example code compile list)
Working Draft 2016, ISO/IEC 14882(1)
https://qiita.com/kaizen_nagoya/items/df5d62c35bd6ed1c3d43/
文書履歴
ver 0.10 初稿 20180612